@article{542ac782c7d948d49e195ad2af31dc31,
title = "Kinetics and mechanism of selenate and selenite removal in solution by green rust-sulfate",
abstract = " This work investigated the removal of selenite and selenate from water by green rust (GR) sulfate. Selenite was immobilized by simple adsorption onto GR at pH 8, and by adsorption-reduction at pH 9. Selenate was immobilized by adsorption-reduction to selenite and zero valent selenium (Se 0 ) at both pH 8 and 9. In the process, GR oxidized to a mixture of goethite (FeOOH) and magnetite (Fe 3 O 4 ). The kinetics of selenite and selenate sorption at the GR-water interface was described through a pseudo-second-order model. X-ray absorption spectroscopy data enabled to elucidate the concentration profiles of Se and Fe species in the solid phase and allowed to distinguish two removal mechanisms, namely adsorption and reduction. Selenite and selenate were reduced by GR through homogeneous solid-phase reaction upon adsorption and by heterogeneous reaction at the solid-liquid interface. The selenite reduced through heterogeneous reduction with GR was adsorbed onto GR but not reduced further. The redox reaction between GR and selenite/selenate was kinetically described through an irreversible second-order bimolecular reaction model based on XAFS concentration profiles. Although the redox reaction became faster at pH 9, simple adsorption was always the fastest removal mechanism.",
keywords = "Green rust, Immobilization, Kinetics, Mechanism, Selenium",
author = "Aina Onoguchi and Giuseppe Granata and Daisuke Haraguchi and Hiroshi Hayashi and Chiharu Tokoro",
note = "Funding Information: Data accessibility. Data available from the Dryad Digital Repository at: https://doi.org/10.5061/dryad.nk43478 [44]. Authors{\textquoteright} contributions. A.O. gave essential contribution to the experimental acquisition of data and to the drafting of the article. G.G. gave substantial contribution to the design of the experiments, analysis and interpretation of data, drafting and revision of the article. C.T. gave substantial contribution to conception of the work, interpretation of data and revision of the article. All authors approve the final version and agree to be accountable for all aspects related to this work. Funding. Authors also wish to thank Mitsubishi Material Corporation (MMC, Japan) for the support received during this research. Competing interests. We have no competing interests. Acknowledgements. A part of the present work was performed within the activities of Research Institute of Sustainable Future Society, Waseda Research Institute for Science and Engineering, Waseda University. The XAFS analysis was performed using the BL5S1 beamline at the Aichi Synchrotron Radiation Center, Aichi Science & Technology Foundation, Aichi, Japan (Proposal no. 2017P1001). Funding Information: A part of the present work was performed within the activities of Research Institute of Sustainable Future Society, Waseda Research Institute for Science and Engineering, Waseda University. The XAFS analysis was performed using the BL5S1 beamline at the Aichi Synchrotron Radiation Center, Aichi Science & Technology Foundation, Aichi, Japan (Proposal no. 2017P1001). Publisher Copyright: {\textcopyright} 2019 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.",
year = "2019",
month = apr,
day = "1",
doi = "10.1098/rsos.182147",
language = "English",
volume = "6",
journal = "Royal Society Open Science",
issn = "2054-5703",
publisher = "The Royal Society",
number = "4",
}